Semiconductor lasers with high output optical power are of interest to many application, including but not limited to optical pumping of fiber and solid state lasers, frequency doubling, and material processing. FIG. 1 schematically shows, in top view, a typical high-power semiconductor laser, which has a high-reflectivity (HR) coated back facet (BF) 1 and anti-reflection (AR) coated front face (FF) 3 in order to concentrate all output optical power of the laser into a single output beam from the front facet 3.
Historically, increasing the cavity lengths L and, where multimode generation is acceptable, the width of the active region, was found to improve the laser output optical power due to better heat dissipation and reduced injection current density. However, the maximum output of conventional high power semiconductor lasers has been limited to rollover power levels of approximately 20 W for broad-area 100 um width lasers, and less for single-mode narrow-area lasers with the waveguide width of a few microns. Accordingly, for applications requiring even greater optical power, optical sources have been developed wherein radiation from multiple high-power lasers is combined in one or two output beams, see for example U.S. Pat. Nos. 8,427,749 and 8,437,086, both of which are assigned to the assignee of the present application and are incorporated herein by reference.
However, there is still a need to provide semiconductor lasers and semiconductor laser based devices with even greater output optical power and improved output efficiency.